<!DOCTYPE html>
<html lang="en">
<head>
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  <meta name="viewport" content="width=device-width, initial-scale=1.0">
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  <title>Document</title>
  <style>
    *{margin:0; padding:0;}
    li{list-style:none;}
    .box{width:100px;}
    ul{overflow:hidden; margin-right:-20px;}
    li{float:left; width:30px; height:30px; background-color:#f00; margin-right:10px;}
  </style>
</head>
<body>
  <div class="box">
    <ul>
            <li></li>
            <li></li>
            <li></li>
    </ul>
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</body>
</html>